FIG. 1 illustrates an example of a conventional electric machine. Referring to FIG. 1, the conventional electric machine is an example of a permanent magnet linear synchronous motor, and includes a mover 10 having phase windings 12, in which U, V, and W phases are repeated on a mover iron core 11 having a three multiple number of teeth, and a stator 20 in which permanent magnets 21 are arranged on a linear stator iron core without using stator salient poles so that the permanent magnets 21 have polarities opposite to those of neighboring permanent magnets.
However, the structure of the conventional linear electric machine is problematic in that as a movement distance is lengthened, the number of permanent magnets used is increased and then cost is inevitably increased, and in that the pulsation of a propulsive force and a attraction force is produced due to end effects occurring at the ends of the inlet and outlet of the mover, so that the linear electric machine is not suitable for the control of precise location.